Credit

Caption

Tubifex worm, coloured scanning electron micrograph (SEM). Tubifex tubifex, also called the sludge worm, or sewage worm, is a species of annelid worm that inhabits the sediments of lakes and rivers. Tubifex are known for their use as water quality indicators, especially in areas with urban and sewage pollution. The forked chaetae (bristles) help in locomotion. Magnification: x50 when printed at 10 centimetres wide.